const Koa = require('koa');
const app = new Koa();

app.use(async  (ctx, next) => {
    await next();
    const rt = ctx.response.get('X-Response-Time')
    console.log(`${ctx.method} ${ctx.url} -${rt}`);
})

app.use(async (ctx, next) => {
    const start = Date.now();
    await next();
    const ms = Date.now() - start;
    ctx.set('X-Response-Time', `${ms} ms`);
})

app.use(async ctx => {
    ctx.body = 'hello world';
})

app.listen(3000);